Siemens PM-E F pm DC24V PROFIsafe Installation And Operating Manual page 54

General Technical Specifications
6.3 Electromagnetic Compatibility
Protecting the ET 200S with Fail-Safe Modules from Overvoltage
If your equipment makes protection from overvoltage necessary, we recommend that you
use an external protective circuit (surge filter) between the load voltage power supply and
the load voltage input of the terminal modules to ensure surge immunity for the ET 200S with
fail-safe modules.
Note
Lightning protection measures always require a case-by-case examination of the entire
system. Nearly complete protection from overvoltages, however, can only be achieved if the
entire building surroundings have been designed for overvoltage protection. In particular, this
involves structural measures in the building design phase.
Therefore, for detailed information regarding overvoltage protection, we recommend that you
contact your Siemens representative or a company specializing in lightning protection.
The following figure illustrates an example configuration with F-modules and standard
modules and the power modules PM-E DC24..48V/AC24..230V and PM-E F pm DC24V
PROFIsafe. Voltage is supplied over four power supplies.
You can also use fewer power supplies. However, you must ensure that the total current of
the modules fed by one power supply does not exceed the permissible limits.
You can also use power modules PM-E DC24V. The protective circuit corresponds to that of
the PM-E DC24..48V/AC24..230V + automatic circuit breaker (as with PM-E F pm DC24V
PROFIsafe).
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ET 200S Distributed I/O System - Fail-Safe Modules
Installation and Operating Manual, 08/2008, A5E00103686-07